Urea constitutes about 45% of the worldwide consumption of nitrogen in agriculture and is the most widely used nitrogen fertilizer. However, after application to soil, urea partially hydrolyzes to ammonia and carbon dioxide, a process catalyzed by native bacterial and fungal ureases. These gaseous products volatilize to the atmosphere and, thus, a substantial amount of the total nitrogen applied to the field is lost.
Urease inhibitors applied together with urea may considerably decelerate this hydrolysis. Among the most effective urease inhibitors are the phosphoric triamide compounds as described in U.S. Pat. No. 4,530,714 (incorporated herein by reference), such as N-(n-butyl)thiophosphoric triamide (NBPT). Phosphoric triamides may also prevent the enzymatic cleavage of urea in animal wastes, thereby decreasing odor. Similarly, the urease inhibitors may mask animal urine odor, thus dissuading animals from undesired territorial behavior, including territorial marking with urine.
Industrial grade NBPT is a solid, waxy compound, which decomposes with moisture and at elevated temperatures. Direct application onto urea particles is very difficult. Thus, what is needed are NBPT solutions which have high solubility and stability of NBPT in the solvent, resistance of the NBPT solutions against crystallization at a low temperature, low viscosity at high concentrations, low toxicity, low volatility and flammability, minimal water content, and low cost.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.